| 摘要 |
Provided is a technique of detecting not only a main DC voltage but also an auxiliary DC voltage to protect a main rectifier circuit and an auxiliary rectifier circuit. A main power supply circuit drives a load. A main rectifier circuit receives an AC voltage through a first switch to supply the main power supply circuit with a main DC voltage. The first switch is turned off when an overcurrent flows through the main power supply circuit or the load is an overload for the main power supply circuit. A control circuit is supplied with operating power from an auxiliary power supply circuit. An auxiliary rectifier circuit receives the AC voltage while bypassing the first switch to supply the auxiliary power supply circuit with an auxiliary DC voltage. A DC voltage detection circuit detects the main DC voltage and the auxiliary DC voltage. |
